mineral

Quartz Vein / Milky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: White to translucent; Luster: Vitreous (glassy) to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 (Mohs scale)
Color: White to translucent
Luster: Vitreous (glassy) to greasy

Identified April 20, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: White to translucent; Luster: Vitreous (glassy) to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed from hydrothermal solutions circulating through fractures in the Earth's crust. As the hot water cools, quartz precipitates and grows into the vein shape. Found across all geological ages, from Precambrian to recent volcanic activity.

Uses & applications

Used in the production of glass, ceramics, and abrasives. High-purity quartz is essential for silicon chips and electronics. It is also used as a decorative stone and for gemstone carving.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. It is piezoelectric, meaning it can generate an electric charge under mechanical stress, which is why it is used in watches and clocks.

Field identification & locations

Identify in the field by its hardness (it can scratch glass), its lack of cleavage, and its characteristic 'greasy' luster on fractured surfaces. Often found protruding from softer surrounding rocks as it is very resistant to weathering.